Abstract: The invention relates to a method and device for measuring and influencing the strip flatness in the coiler shaft of a hot-strip mill, whereby the coiler shaft has, between a driver and a coiler, moving and stationary strip guides as well as a flatness measuring roll (13). The hot strip (1) is supplied via the coiler shaft to a coiler, which is provided with a coiler mandrel (5), pressure rolls (6) and with deflecting shells (7), over a roller table (2) and the driving rolls (3, 4) of the driver. The flatness measuring roll (13) is displaced out of a working position, in which the hot strip is guided around the flatness measuring roll (13) while maintaining an approximately constant contact angle ?, and into a lowered position. In addition, a strip guide (14), which can swivel inward and protects the flatness measuring roll (13), is placed inside the coiler shaft.